1. Field of the Invention
The present invention concerns an assembly of pots for raising and transplating seedlings (hereinafter simply referred to as pots) and, more particularly, it relates to pots having tongue-like pieces formed in the side walls by providing a very fine pattern of cuts to the side walls of each pot during manufacture.
2. Description of the Prior Art
A culture method for raising plant seedlings by using a pot made of paper or a paper-like thin film and then transplanting the thus obtained potted seedlings to a field has been generally used.
Most such pots used to culture plants are of a cylindrical form without top and bottom in which soils are added, seeds are sown, water is applied and then seedlings are raised for a predetermined period and the resultant seedlings are transplanted together with the pot to a field.
After the transplantation, since the pot gradually decomposes in the earth, roots of the seedlings can freely form and extend to make subsequent growth favorable. However, since the decomposition of the pot may be retarded due to the differeing quality of field soils, extension of the roots out of the pot may also be inhibited under such conditions thereby hindering plant rooting and subsequent growth.
In order to overcome such a disadvantage, there have been proposed, for example, cylindrical pots each open at both the upper and lower ends and having plural rows of holes passing through the circumferential surface thereof, as disclosed in the specification of Japanese Utility Model Laid-Open Sho 59-193251; and pots in which small apertures are perforated in the circumferential surface of the pot so as not to allow communication between adjacent pots as disclosed in Japanese Utility Model Publication Sho 51-12362.
However, the pots containing such small apertures at the side wall of the pot involve the following problem which must be overcome in practice.
That is, in the cylindrical pots open at both the upper and lower ends and having plural rows of holes formed in the circumferential surface as disclosed in Japanese Utility Model Laid-Open Sho 59-193251, since the holes in the side walls of the individual pots are arranged uniformly (refer to FIG. 1 of the publication), when the pots are used for raising seedlings and assembled together, the holes in the side walls of adjacent pots are in communication with each other (refer to FIG. 2 of the publication), roots of seedlings in adjacent pots entangle through the communication holes during raising making it difficult to separate them into individual potted seedlings after the completion of raising. Further, in the pots having small holes such that they are not in communication with the holes of adjacent pots, as disclosed in Japanese Patent Publication Sho 51-12362, entanglement of roots between the adjacent pots is eliminated during raising, however, an extremely complicated manufacturing step is required to provide such a structure with small holes in the side walls so as not to be in communication with the holes of adjacent pots.
In addition, individual pots are usually assembled by forming a strip-like body by successively connecting a predetermined number of collapsed hollow cylindrical bodies while overlapping them each at a 1/2 or 1/3 width to each other, laminating a predetermined number of such strip-like bodies and bonding between the adjacent layers by means of a water soluble paste. However, in the two types of assembled pots described above, since holes or small holes are formed at a portion constituting the side walls of the unassembled pot, paste coated between the adjacent laminated layers would adhere to surfaces not required to be bonded after passing through the holes, large or small, and hinder seedling development in the assembled pots.
In view of the foregoing, a need has been felt for an assembly of pots useful for rearing and transplanting seedlings that is free from structural problems and capable of allowing vigorous extension of roots out of the pots after transplantation.